During the flight of an aircraft, in particular during a low-altitude flight taking place automatically (by an auto-pilot device and/or a flight director), onboard systems can be made to modify the path followed by the aircraft (laterally and vertically) at the request of a pilot of the aircraft.
In order to do this, the pilot modifies the flight plan using a flight management system of the aircraft. The flight management system calculates a new (lateral and/or vertical) path corresponding to the modified flight plan. The calculation of this new path may last for several seconds. During this time period, the aircraft has to continue to fly on the current path, before the change can potentially be made.